Weddings and Spring Festival

Hey all, I need some advice! My Chinese friend is getting married right before Spring Festival and now, not only am I going to the wedding, but for 10 days - over the Spring Festival - I will be staying with her soon-to-be-husband's family. I am so nervous! My Chinese is not so good and there are so many cultural mistakes I could possibly make. Please, please any pointers all of you might have would be helpful - or any stories you have to share!

Should I bring a gift for the family? What? How much should I give in the hóngbāo 红包? She bought my plane tickets and probably won't let me pay her back (in traditional Chinese fashion), so I think I will give them more money in the hóngbāo. I am sneaky. Haha. :P